British Patent No. 1,434,826 describes esters and carbamates of amino alcohols having the general formula: ##STR2## in which R.sub.1, R.sub.2 and R.sub.3 are hydrogen, alkyl, hydroxyalkyl, trifluoromethyl or halogen, R.sub.4 is hydrogen, alkyl, cycloalkyl or aryl, R.sub.5 and R.sub.6 are hydrogen, alkyl, or aryl alkyl or together form a heterocyclic structure, and x, y and z are zero or one, R.sub.7 being alkyl, aryl alkyl, aryl, aryl alkenyl, diaryl alkyl, aryl cycloalkylalkyl, heteroaryl, amino or amino-substituted.
These compounds are reported to be inhibitors of gastrointestinal spasms and peristalsis; some of them have analgesic properties, combined with a remarkable absence of activity with regard to the central nervous system.
In the French patent application published under No. 2,690,917, the applicant describes an invention which has as its object new aminoesters of the formula: ##STR3## in which: R.sub.1 is H or low-molecular-weight alkyl, R.sub.2 is low-molecular-weight alkyl, low-molecular-weight phenylalkyl, low-molecular-weight cycloalkylalkyl; or R.sub.1 and R.sub.2 together, with the nitrogen atom to which they are bound, form a five- to seven-chain saturated heterocyclic compound which can comprise a second heteroatom such as oxygen not juxtaposed with nitrogen; R.sub.3 is low-molecular-weight alkyl, cycloalkyl, or low-molecular-weight phenylcycloalkyl, pyridyl, or phenyl, low-molecular-weight phenylalkyl, low-molecular-weight diphenylalkyl, optionally hydroxylated, low-molecular-weight phenylalkenyl, optionally mono-, di- or trisubstituted by chlorine atoms, low-molecular-weight alkyl radicals, low-molecular-weight alkoxy, or trifluoromethyl, acetamide or acetyloxy radicals.
These compounds exhibit analgesic properties associated with action on the central nervous system (CNS), while having no effects on the gastrointestinal tract.